Generally, Ethernet is connected using twisted pair cabling. According to the 1000Base-T standard, Ethernet needs four twisted pairs to operate normally. For example, reference is made to FIG. 1, which shows a diagram of an Ethernet connection method according to 1000Base-T standard. Ethernet 1 includes an Ethernet wire 11 and two Ethernet devices 13a, 13b connected to each other by the Ethernet wire 11, and the data transmission rate of each of the twisted pairs 11a-11d in the Ethernet wire 11 is 250 Mbps. Therefore, a total transmission rate of the four twisted pairs 11a-11d is 1 Gbps. However, according to the 10Base-T or the 100Base-TX standard, Ethernet 1 only needs two of the twisted pairs to operate normally, and it is thus common that only two twisted pairs capable of transmitting data are provided in the wiring of conventional carriers.
Therefore, when a user uses an Ethernet device supporting a transmission rate over 1 Gbps to connect via a conventional wiring with an Ethernet device on the other end thereof also supporting a transmission rate over 1 Gbps, since an additional two twisted pairs are not included in the conventional wiring and it is not matching the 1000Base-T standard, these two Ethernet devices with transmission rate over 1 Gbps are limited by an inadequate number of usable twisted pairs. Accordingly, experience connection is failure and forced to use the 100Base-TX/10Base-T standards to transmit data such that the performance of the two Ethernet devices is affected.